Planetology Help

[Garnfellow]

So I've got a system with an F6 D star (whatever that is), 5 gas giants, and no planetoid belts. Is this possible? Plausible?

If so, would it be possible to have a terra-norm world somewhere in this system? Would it have to be a moon orbiting one of the gas giants?

 

[robject]

Realistically, based on our model of how the universe works, no it's not real, and a T-norm world wouldn't be there. Nor would gas giants.

A "D" is a dwarf star, and it's basically in its final, terminal phase of existence; it's basically dead, and just starting to cool off (it will take a long time to cool off, but still...). To become a dwarf, the star first expanded to gigantic proportions and gobbled up the entire insystem, warming or even cooking several more orbits out at the same time. Then it shrank to be even cooler than a "main sequence" star like our sun. A relatively cold cinder with low mass, I believe.

Our sun will go through this process in a billion years or less.


Based on Traveller, it's possible. Call it intervention, or call it new knowledge that transforms our understanding of the stellar life cycle (something new happening we've never even thought was possible). Unlikely... but this is science fiction, for goodness' sake. Even astronomers are willing to enjoy improbables and fantastic settings.

A moon around one of the GGs is a safe bet, or perhaps a wandering planet that was captured late and is in close orbit around the dwarf... close enough to be warmed. Orbit 1, or even 0. Maybe 2, if you don't mind stretching things a tad.

 

[stealth]

Class F is main sequence, white in color, rich in heavy metals - a white sun.

Wiki says 1/33 of main sequence stars are class F.

I don't know if a garden world could orbit a gas giant: it would have to be far enough away to escape tidal effects and the magnetic field of a world with a metallic hydrogen core (as all gas giants have). So it would have to be in a distant satellite orbit.

Also, the parent gas giant would have to be in the life belt at about the orbit of Earth, say 96 million miles about the sun.

Does that help?

 

[stealth]

I don't think so.

Realistically, based on our model of how the universe works, no it's not real, and a T-norm world wouldn't be there. Nor would gas giants.

A "D" is a dwarf star, and it's basically in its final, terminal phase of existence; it's basically dead, and just starting to cool off (it will take a long time to cool off, but still...). To become a dwarf, the star first expanded to gigantic proportions and gobbled up the entire insystem, warming or even cooking several more orbits out at the same time. Then it shrank to be even cooler than a "main sequence" star like our sun. A relatively cold cinder with low mass, I believe.

Our sun will go through this process in a billion years or less.

I think it's a white version of a yellow dwarf, hence "main sequence", and not real quasi-crystal quantum whatever remnant star core white dwarf (type VII).

 

[aramis]

F6 D is also F6 VII.

Class F doesn't indicate main sequence; it indicates a yellowish-white star of about 6600°K surface temp. The D indicates class VII. Which is NOT main sequence.

It's a white dwarf with a yellow-white color.

Any GG's would have had to survive the shedding event near the end of it's former main sequence life... and then spiraled in. It's possible that such spiral in could have pulled some rocky bodies in, too.

 

[stealth]

Ah. My bad.

F6 D is also F6 VII.

Class F doesn't indicate main sequence; it indicates a yellowish-white star of about 6600°K surface temp. The D indicates class VII. Which is NOT main sequence.

It's a white dwarf with a yellow-white color.

Any GG's would have had to survive the shedding event near the end of it's former main sequence life... and then spiraled in. It's possible that such spiral in could have pulled some rocky bodies in, too.

In that case, start searching for artifacts - Grandfather was there.

 

[Garnfellow]

Thanks, guys -- this is more-or-less what I expected. (This particular system just happens to be one implausibility upon another.)

So let's say we jettison the stellar data and assume it's in error. We have 5 gas giants, no planetoid belts, and somewhere . . . one Terra norm planet. Is there a star that would plausibly work with those parameters?

 

[aramis]

Doing as little changing as possible: change it from an F6 D to an F6 V and you get a main sequence star a little hotter than our own, and a teensy little more blueish light. (By daylight it's too bright to matter to the human eye; too close. From a distance, it looks a little whiter than Sol.)

Given recent findings with extrasolars, 5 GG is no biggie (Sol has 4: Jupiter, Saturn, Uranus, Neptune), and a T Norm in orbit 4 (Mars Orbit, FYI, so expect a year of about 450 days). Orbits 0-3 can be rocky, 5-12 are where to place the GG's, and a 1/3rd chance of 1-3 empty orbits exists. Max orbit number is 2d6 (in this case minimum 5) which would put GG's into orbits 0-3 and 5...
Anyway...

Worlds: Roll 2D-2 for World Size.
If orbit 0, DM-5;
if orbit 1, DM-4;
if orbit 2, DM-2.​

Filling in what's left.
We know now that GG's can be inside the Hab Zone (For an F6, about mars orbit), but traveller says not to place them in the inner or hab zones unless there are too many for the available outer zones.

 

[Peter Schutze]

making it an F6v could easily get you a solar system not too different to ours

depending on the planetoid roll you could easily copy ours and make the asteroid belt the (small for realisms sake) 5th giant

the actual orbit distances would stretch out a bit .... Mars would be comfortably inside the habiltable zone of an F_v

 

[Garnfellow]

Now that it's been suggested, I seem to remember that TNE materials errata'd a lot of older stellar data . . . and wasn't one of the changes to replace all main stars with a D to a "V"? Or perhaps I am misremembering.